Trying to run JUnit test but getting an ERROR: Implementing class - testing

Question

I'm trying to run a simple test with following class (DataStructureTest) code:
public class DataStructureTest extends DatabaseTestCase {
private static final Log log = (Log) LogFactory.getLog(DataStructureTest.class);
#Test
public void testProductData(){
//Creating a product data
log.debug("Creating new product data");
ProductData productData = new ProductData("Öljy");
//Setting basic information of product
log.debug("Setting basic information like name, price, description "
+ "and amount.");
productData.setProductPrice(4.13);
productData.setProductDescription("Öljy rekoille.");
productData.setProductAmount(20);
//Saving entity
EntityManager em = getEntityManager();
EntityTransaction tx = em.getTransaction();
tx.begin();
em.persist(productData);
Integer primarykey = productData.getId();
tx.commit();
//Reading entity from database
log.debug("Reading entity data from database.");
tx = em.getTransaction();
tx.begin();
productData = em.find(ProductData.class, primarykey);
tx.commit();
//Asserting that the product data was correct in database
Assert.assertEquals("Product name was correct", "Öljy",
productData.getProductName());
Assert.assertEquals("Product price was correct", 4.13,
productData.getProductPrice());
Assert.assertEquals("Product description was correct", "Öljy rekoille",
productData.getProductDescription());
Assert.assertEquals("Product amount was incorrect", 21,
productData.getProductAmount());
}
}
DatabaseTestCase class code is following:
public class DatabaseTestCase {
/**
* This method establishes Entity Managerin before every test
* and writes information into log.
*/
private static final Log log = LogFactory.getLog(DatabaseTestCase.class);
private EntityManager entityManager;
private EntityManagerFactory entityManagerFactory;
#Before
public void establishEntityManager(){
log.debug("Establishing database connection!");
entityManagerFactory = Persistence.createEntityManagerFactory("warehouseTestPersistence", null);
entityManager = entityManagerFactory.createEntityManager();
}
#After
public void closeEntityManager(){
if(entityManager != null){
entityManager.close();
} else {
log.warn("Entity was empty (null) in tests.");
}
}
public EntityManager getEntityManager(){
return entityManager;
}
/**
* #param entityManager the entityManager to set
*/
public void setEntityManager(final EntityManager entityManager) {
this.entityManager = entityManager;
}
/**
* #return the entityManagerFactory
*/
public EntityManagerFactory getEntityManagerFactory() {
return entityManagerFactory;
}
/**
* #param entityManagerFactory the entityManagerFactory to set
*/
public void setEntityManagerFactory(final EntityManagerFactory entityManagerFactory) {
this.entityManagerFactory = entityManagerFactory;
}
/**
* Save entity to database. Used for assisting in tests.
* #return primary key for specific entity.
*/
protected Integer saveEntity(Entityclass entity){
EntityManager em = getEntityManager();
EntityTransaction tx = em.getTransaction();
tx.begin();
em.persist(entity);
tx.commit();
return entity.getId();
}
/**
* Load entity from save location.
* #param <T>
* Generic class.
* #param entityclass
* Entity class of entity that is going to be loaded.
* #param primarykey
* Entity class primary key.
* #return correspondant entity.
*/
protected <T extends Entityclass> T loadEntity(final Class<T> entitysclass, final Integer primarykey){
EntityManager em = getEntityManager();
EntityTransaction tx = em.getTransaction();
tx.begin();
T entity = em.find(entitysclass, primarykey);
tx.commit();
return entity;
}
}
I use NetBeans 7.0.1. All imports for both class are done properly. I have also added all required dependencies. But whenever I run a test I get following result:
-- error field --
No test passed, 1 test caused an error.(0,075 s)
com.mysite.warehouseapp.DataStructureTest FAILED
testProductData caused an ERROR: Implementing class
Implementing class
java.lang.IncompatibleClassChangeError
at....
at com.mysite.warehouseapp.test.DatabaseTestCase.establishEntityManager(DatabaseTestCase.java:36)
-- test result field --
Establishing database connection!
Entity was empty (null) in tests.
if you see the test result image at top I don't know how it got there but it supposed to be in this location.
So briefly said whenever I try to run the test there's no entity. Can anybody tell me the reason? I have tried to find solution for this problem for four days but still with no luck. Any help is appreciated.
Thanks

Answer 1

I found the solution my ownself, which is quiet rewarding :). Anyway the solution for this problem was that the persistence.xml was in wrong folder. And for newbies, I would advice you to put persistence.xml under following folder in your project src/main/resources/META-INF/persistence.xml.
If you don't have resources/META-INF folder created under src/test, then create one and place your persistence.xml file there. I hope this helps somebody :)
Another thing which I found out was that you might have different jars that are "against" each other and thus you need to take out those jars then it will work.